Cadence Acoustics CAP4DR 4-Farad Power Capacitor 4 Farad/12 Volt Stiffening Capacitor with 24 Volt Surge Capacity Lucite Encapsulated Display and Logic Circuitry Red LED Digital Voltage Display Blue Led Flashing Charge and Discharge Metering IC Controlled circuitry with negative polarity built-in protection Cadence CAP4DR 4 farad 24V capacitor